Meren of Clan Nel Toth

Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.

Accursed Marauder

When this creature enters, each player sacrifices a nontoken creature of their choice.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Malakir Mire

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Massacre Wurm

When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Gray Merchant of Asphodel

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Fell Mire

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Fell the Profane

Fell the Profane // Fell Mire

Avenger of Zendikar

When this creature enters, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land you control enters, you may put a +1/+1 counter on each Plant creature you control.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Abyssal Gorestalker

When this creature enters, each player sacrifices two creatures of their choice.

Sol Ring

Sakura-Tribe Elder

Sacrifice this creature: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Forest

Garruk's Uprising

When this enchantment enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever a creature you control with power 4 or greater enters, draw a card.

Elemental Bond

Whenever a creature you control with power 3 or greater enters, draw a card.

Swamp

Plaguecrafter

When this creature enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to that card's mana value.

Kenrith's Transformation

Enchant creature
When this Aura enters, draw a card.
Enchanted creature loses all abilities and is a green Elk creature with base power and toughness 3/3. (It loses all other card types and creature types.)

Garden of Freyalise

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {G}.

Disciple of Freyalise

When this creature enters, you may sacrifice another creature. If you do, you gain X life and draw X cards, where X is that creature's power.

Disciple of Freyalise // Garden of Freyalise

Command Tower

Spore Frog

Sacrifice this creature: Prevent all combat damage that would be dealt this turn.

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.